1. The Field of the Invention
The present invention relates to an apparatus and method for selectively preventing free flow during enteral or parenteral administration of solutions through an infusion line. More particularly, the present invention relates to an occluder/valve and method of use for infusion sets and the like, wherein the occluder/valve prevents undesirable free-flow of solution through the infusion set while allowing a health care worker to place the infusion set in a free-flow condition to facilitate the rapid delivery of fluids to a patient.
2. State of the Art
The use of infusion sets to administer solutions to patients is well known in the medical arts. Infusion sets are used for both enteral and parenteral applications. Enteral feeding pumps are used to provide patients with nutrition and medication when they are unable, for a variety of reasons, to eat normally. Parenteral (intravenous) solutions are provided to patients to ensure adequate hydration and to provide needed nutrients, minerals and medication. Often, the infusion set is placed in a free standing arrangement in which gravity forces the solution into the patient. The rate at which the solution enters the patient can be roughly controlled by various clamps, such as roller clamps, which are currently available on the market.
In many applications, it is necessary to precisely control the amount of solution which enters the patient. When this is the case, a regulating device, such as an enteral feeding pump or an IV pump, is placed along the infusion set to control the rate at which the solution is fed to the patient. In applications where a pump, etc., is used, the clamp used to regulate flow is typically opened to its fullest extent to prevent the clamp from interfering with the proper functioning of the pump. The clamp is opened with the expectation that the enteral feeding pump will control fluid flow through the infusion set. However, emergencies or other distractions may prevent the medical personnel from properly loading the infusion set in the enteral feeding pump.
When the infusion set is not properly loaded in the pump and the clamp has been opened, a situation known as free-flow often develops. The force of gravity causes the solution to flow freely into the patient unchecked by the pump or other regulating device. Under a free-flow condition, an amount of solution many times the desired dose can be supplied to the patient within a relatively short time period. This can be particularly dangerous if the solution contains potent medicines and the patient's body is not physically strong enough to adjust to the large inflow of solution. In fact, there have been numerous occasions in which the patient has died due to the over-infusion of fluid during a given amount of time. Thus, preventing an undesirable free-flow state is highly desirable.
Numerous devices have been developed in an attempt to prevent free flow conditions. Such devices, however, add to the overall cost of the infusion set and some provide only marginal protection against free flow. Others may have other limitations which limit the usefulness of the occluder.
One popular occluder is described in U.S. Pat. No. 5,704,584 (Winterer et al.). The '584 patent teaches an occluder which is disposed around the outside of an infusion set to selectively prevent fluid flow. The occluder is biased into a closed position wherein the occluder stops flow through the infusion set. The biasing can be overcome by manually holding the occluder open, or by mounting the occluder in a pump and then closing a door so that the door holds the occluder open.
An alternate to such an occluder is shown in U.S. Pat. No. 6,595,950 (Miles et al.). The '950 patent teaches an occluder which is disposed inside the infusion set to selectively block fluid flow from passing through the infusion set. The occluder disclosed in the '950 patent can be overcome either by applying force to the infusion set in such a manner as to open a passage between the wall of the infusion set and the occluder, or by applying sufficient pressure to the feeding or infusion solution to cause the infusion set to radially expand and open a flow channel past the occluder.
While preventing unintended free-flow situations is important, there are also times in which a free-flow condition is desired. This is particularly true when a patient's heart has stopped or other emergency situations. Often medicines will be injected into an IV solution being administered to the patient with the desire that the solution and medicine enter the patient as quickly as possible. If the infusion set uses one of the above referenced occluders, the medical staff must ensure that free-flow conditions are being allowed. This may mean removing the infusion set from the pump in which it is housed and manually holding open the occluder. It is typically not desirable that a person must hold the occluder open, as each member of the medical staff has important duties during an emergency situation. Thus, it is desirable for medical staff to be able to lock the occluder open in an emergency or other situation in which a free-flow condition is specifically desired.
Several occluders can be locked in an open position. For example, U.S. Pat. No. 4,634,092 (Daniell et al.) teaches an occluder which is biased closed. A pin may be inserted into a pair of apertures to hold the occluder in an open position. Such occluders, however, are disadvantageous because the pin can be lost during the commotion involved with an emergency and the occluder may be left in a biased closed condition.
Still another occluding system is shown in U.S. Pat. No. 5,257,978 (Haber et al.). The '978 patent shows a safety module in which a spring is biased to pinch closed tubing of an infusion set. The spring can be pushed into an open position where it allows flow through the infusion set by pressing down on a locking trigger. The locking trigger can also be moved into a locked position wherein the spring is held in an open position. The occluding system shown in the '978 patent is disadvantageous, as it is relatively bulky. Additionally, if the trigger is disposed in the locked open position, the module cannot be properly loaded into a pump, as the pump door will not close.
Thus, there is a need for a device having a default position that prevents a free-flow condition when not properly mounted in a pump, etc., while allowing controlled flow through the infusion set during normal use, and which also allows for a free-flow condition when desired by medical personnel. It is also desirable to provide such a device which is relatively inexpensive and easy to use.